Prevalence of anticentromere antibody in blood relatives of anticentromere positive patients.

Anticentromere antibody (ACA) was investigated in 116 blood relatives of 22 ACA positive patients affected with scleroderma and, for comparison, in 82 healthy subjects matched for age and sex who belonged to 25 families. No relative showed any evident scleroderma symptom although in 8 an unusual cold sensitivity of the extremities was present. ACA at a low titer (40), was found in 4 relatives (3.44%), while it was absent in control sera. The 4 ACA positive relatives were first as well as second degree relatives of probands. Two had familial disease: one idiopathic chronic hypoparathyroidism and the other mental retardation. The third had myasthenia gravis and the fourth unusual cold sensitivity and allergic dermatitis. At present we cannot explain the significance of ACA occurrence in relatives of ACA positive patients. Followup clinical and serological studies could show a possible association of low titer of ACA with subclinical scleroderma features in patients who later develop overt disease.